1. Field of the Invention
The present invention relates to electrical systems for outdoor power equipment, and more particularly, to an interactive or integrated electrical switch system and method for outdoor power equipment.
2. Description of the Prior Art
Microprocessor circuits have largely replaced hard-wired logic circuits in many applications because of their greater flexibility and lower cost. However, in the field of outdoor power equipment, those of skill in the art have not fully utilized the advantages of microprocessors and continue to utilize multiple-pole (xe2x80x9cmulti-polexe2x80x9d) or multiple-throw (xe2x80x9cmulti-throwxe2x80x9d) switches in electrical systems for outdoor power equipment.
One example of this is the continued use of multi-pole and multi-throw switches in the electrical systems of lawn mowers, tractors, and other outdoor equipment. In FIG. 1 of this specification, labeled xe2x80x9cPrior Art,xe2x80x9d there is illustrated one example of a known electrical system for an outdoor power machine that uses a three-pole PTO (power take-off) switch, a two-pole seat switch, and a two-pole brake switch. All of those switches are interconnected via a wiring harness to effect the desired interactions and overall system function.
Since each multi-pole or multi-throw switch in an electrical system generally performs a function independently of other switches, a system using this prior art approach will require many different switches. The prior art approach also complicates assembly and stocking and increases cost. Of course, multi-pole switches are not only less reliable than simple single-pole switches, they are also much more expensive. The use of single-pole switches throughout the electrical system of an outdoor machine, and especially the use of a single design of single-pole switch, advantageously leads to reduced cost, greater reliability, and easier repair.
Another example prior art electrical systems for motors used in outdoor power equipment electrical systems is disclosed in U.S. Pat. No. 6,170,241 issued to Shibilski et al. This patent discloses two multi-pole switches 14 and 16 in a microprocessor circuit in a lawnmower.
U.S. Pat. Nos. 6,135,230 and 6,186,200 issued to Schenck et al. disclose an electrical system for a skid steer loader incorporating a microprocessor and multi-pole switches, the interaction of which is embodied in hard-wired logic. Schenck et al. teach that arm rest and seat switches are wired or coupled in series such that the switch signals inputted to the electronic controller are tied together in a particular manner, that is, using hard-wired logic. In all of their drawing figures, Schenck et al. disclose a double-throw armrest switch coupled to the seat switch.
U.S. Pat. No. 5,188,069 to Fiorenza, II, discloses single-pole switches coupled to respective pins of a microprocessor in an electrical system for a riding lawnmower. The objective of the Fiorenza invention is to defeat safety-switch tampering. The three switches are a seat switch closed when the operator is sitting on the seat, a transmission switch closed when the transmission is in neutral, and a power take off (PTO) switch closed when the power take off is disengaged.
The microprocessor of the Fiorenza apparatus remembers the history of each safety switch, and will not allow the lawnmower to run unless each switch has been closed after being open. This defeats tampering with the switches by shorting across them or taping them in the closed position; such a switch will not have been open, it will only have been closed. For his memory, Fiorenza discloses logic gates and flip-flops. The AND gates are needed because of the flip-flops, but without those memory devices, a simple series connection of the three switches would be adequate. Fiorenza does not disclose any multi-pole switches in the equivalent hard-wired circuit of his drawings. Moreover, the Fiorenza microprocessor does not operate in xe2x80x9creal timexe2x80x9d.
In view of the limitations of the prior art devices as discussed above, it would be desirable in outdoor power equipment to replace hard-wired circuits with processors, and more particularly to specifically and systematically eliminate any switches other than single-pole, single-throw switches.
In view of the aforementioned deficiencies in the prior art, the present invention is directed to the use, in an outdoor power machine, of single-pole switches coupled directly to a microprocessor programmed to incorporate the logic of the interconnections between the poles of the multi-pole or multi-throw switches. More particularly, the invention contemplates systematically replacing all multi-pole and/or multi-throw switches with single-pole, single-throw switches.
The present invention further contemplates replacing each multi-pole or multi-throw switch with a virtual multi-pole or multi-throw switch. Such a virtual multi-pole or multi-throw switch might include a microprocessor coupled to the power-controlled devices of the electrical system, a single-pole, single-throw switch coupled to an input of the microprocessor, and a program in the microprocessor simulating multi-pole or multi-throw switches interconnected among the other parts of the electrical system or among themselves. As used herein, the term xe2x80x9cvirtual multi-pole or multi-throw switchxe2x80x9d refers to the use of the combination of a single-pole switch coupled to a processor.
In a microprocessor-based electrical system, any interactions between various components can be programmed, and therefore the logic embodied in the interconnections between the extra poles of multi-pole switches, which are coupled to different components, can be embodied in a microprocessor coupled to single-pole switches and the same components.
The invention has several objects, namely:
(1) to achieve greater design flexibility and simplify redesigns of electrical systems for outdoor power machines;
(2) to decrease costs by replacing expensive multi-pole switches with inexpensive single-pole switches in the electrical systems for outdoor power machines;
(3) to increase reliability by using simpler and more rugged single-pole switches; and
(4) to reduce a number of different parts to be stocked, assembled, and replaced, to one single part, a single-pole switch of a single design.
With these and other objects, advantages and features of the invention that may become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the following detailed description of the invention, the appended claims and to the several drawings attached herein.